The operating frequencies of a variety of electronic equipment have increased in recent years, and with such an increase in operating frequencies, piezoelectric resonator devices (e.g., crystal resonators or the like) are also required to take measures against such an increase in operating frequencies.
Piezoelectric resonator devices of such kinds include first and second sealing members of glass and a crystal resonator plate made of crystal and having driving electrodes formed on both major surfaces; the first sealing member and the second sealing member are laminated and bonded together via the crystal resonator plate so as to hermetically seal the driving electrodes of the crystal resonator plate located inside the sealing members (see Patent Document 1 described below, for example).